Wall block



FIG. 1 is a perspective view of a wall block showing my new design;

FIG. 2 is a top view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a side view thereof, the opposite being a mirror image thereof;

FIG. 5 is a front view thereof; and

FIG. 6 is a rear view thereof. 

The ornamental design of a wall block, substantially as shown and described. 